Cellular terminals can be used in many different environments. Increasingly, terminals will be used in environments where they are subject to moisture or fine dust. Therefore there are terminals on the market in which the cover parts constitute a dustproof and waterproof structure assembled of two separate components. The speaker element in the terminal resides within this waterproof structure.
In some respects such a structure is problematic. First, the audio level produced by the speaker element in this kind of an arrangement is so low that the user of the terminal has to place the terminal close to his ear. The terminal cannot be used hands free because the audio level is not sufficient for that kind of use.
Making the speaker element dustproof and waterproof means usually that a sealing diaphragm has to be placed in front of the speaker element, which diaphragm with its fastening structures will result in that the terminal must be designed and fabricated a few millimeters thicker so that said isolating diaphragm can be positioned at the right distance from the speaker element.